The present invention is directed to magnetic disk information storage systems, and more specifically to structures associated with a movable carriage for one or more read-write heads.
In magnetic disk systems, bits of information are typically stored in concentric circular tracks on one or both surfaces of the disk. An electromagnetic transducer, or "head", located in close proximity to the recording surface is used to write the information on the disk, and subsequently read it, while the disk is continuously rotating. Data recovery involves detecting the presence of flux transitions beneath a selected head. Magnetized particles that pass beneath the head gap generate a current flow in the head circuit. The direction of current is determined by polarity of this magnetic field.
To enable the head to access the various tracks on the disk, it may be mounted on a movable carriage so as to be translatable in a generally radial direction. The carriage may take the form of a pivotable tone arm type of arrangement, similar to that seen on many phonographic turn-tables, in which the head moves along a generally radial path across the surface of the disk. Alternatively, the carriage can be arranged to linearly translate along a track defining a path radial with respect to the axis of rotation of the disk.
Initially such magnetic disks were relatively large and employed relatively large storage disks or drums, e.g. 14 inches or greater in diameter. Because of trends toward the reduction in size of computer systems in general, a demand has resulted for smaller disk storage systems, such as a Winchester disk drive system with a 51/4 inch hard disk.
It is a general object of the present invention to provide techniques for producing small, economical disk drive systems.
In the moving carriage systems, electrical connections must be made between each transducer head and stationary amplifier circuitry attached to the system chassis. In the past, single "U" shaped cable loops have been employed to provide the necessary "play" between the carriage and chassis. Two such prior art cables are illustrated in FIGS. 5a and 5b, discussed below. U.S. Pat. No. 4,285,018 to Mulvany et al discloses a disk drive system employing a "U" shaped cable 42 which connects radially driven heads to a stationary panel connector 76. U.S. Pat. No. 4,331,991 to Morehouse et al and U.S. Pat. No. 4,346,416 to Riggle et al show "U" shaped ribbon cables connecting moving "tone arm" mounted heads to stationary portions of the respective systems.
Reduction in size of the disk drive system severely limits the space available for a free-flexing cable. Cable fatigue, excessive cable length and excessive or uncontrolled cable excursion also present design problems.
It is an object of the present invention to provide a flexing connector cable assembly which has a compact configuration.
It is another object of the present invention to provide a flexing connector cable assembly and associated system layout which has a compact configuration.
It is another object of the present invention to provide a flexing connector cable assembly and associated systems layout which reduces overall cable length between the heads and a system pre-amplifier.
It is another object of the present invention to provide a flexing connector cable assembly which has a compact arrangement configured to reduce fatigue on the cable caused by the flexing.
It is another object of the present invention to provide a flexing connector cable assembly which has a compact configuration which inhibits unwanted cable excursion from a defined volume within the system.
Reduction in size of disk drive systems and the requirements from higher density information storage has created difficulties in the provision of components with acceptable dimensional and alignment tolerances. This is particularly true with carriage and carriage drive mechanisms. Distances on the order of 0.0004 inches can determine whether the transducer heads are positioned on the correct information streams.
In the past, carriages have been driven along a track by a stepper motor coupled to the carriage by a band actuator. A prior art band actuator is shown in FIG. 7 and discussed below. Problems are encountered in the prior art system if the stepper motor, bands and carriage arms, to which the bands are attached, are improperly dimensioned or aligned. Excessive band wear and mis-positioning of the heads may result.
Accordingly, it is an object of the present invention to provide a band actuator system which allows for slight deviations in the size and alignment of the associated system components.
It is another object of the present invention to provide a band actuator system which inhibits band wear and mis-positioning.
A related problem in carriage systems involves the tracks and bearings which constrain the carriage to move along a radial path in response to the band actuator.
It is another object of the present invention to provide a small, inexpensively fabricated, high tolerance carriage and track system for a magnetic disk system.
These and other object and features will be apparent from the description of the invention contained herein including the claims.